Combined steam engine and pulverulent fuel feeding device



Feb. 6, 1934. 1,945,778

COMBINED s'I I M ENGINE AND PULVERULENT FUEL FEEDING DEvIcE A. M. HUNT 3 Shets-Sheet 1 Filed May 6, 1930 W ATTORNEY Feb. 6, 1934. E A. M. HUNT 1,945,778

COMBINED STEAM ENGINE AND PULVERULENT FUEL FEEDING DEVICE Filed May 6, 1930 3 Sheets-Sheet 2 IN VENT OR LMWt I A TTORNE Y A. M. HUNT Feb. 6, 1934.

COMBINED STEAM ENGINE AND PULVERULENT FUEL FEEDING DEVICE Filed May 6, 1950 3 Sheets-Sheet 3 Patented Feb. 6, 1934 UNITED STATES PATENT OFFICE COMBINED STEAM ENGINE AND PULVERU- LENT FUEL FEEDING DEVICE Application May 6, 1930. Serial No. 450,100

1 Claim.

This invention relates to combined steam engines and pulverulent fuel feeding devices therefor, and more particularly to the construction and arrangement of the water containing and conducting members or steam generating elements and to the positioning of the fuel feeding nozzles relative thereto.

The use of pulverulent fuel for generating steam in locomotive boilers has been limited necessarily, and such installations have been very few because of the difficulties encountered in its use. Primarily there are two major difiiculties, namely, insufficient furnace volume, and slag or honeycomb forming on the boiler flue sheet eventually plugging or restricting the boiler tubes or fiues. Honeycomb is the term given to the molten slag or ash formation adhering to the flue sheet. Such honeycomb is composed largely of ash which does not burn; and in some coals the ash content is high as 20% and is as finely divided as the coal. In the presence of the high temperature existing in the boiler ignition or combustion chamber the ash softens, becoming sticky or tacky, and in this condition it will adhere to the first cooler surface it meets, which surface is ordinarily the boiler flue sheet. This honeycomb accumulates and often attains a thickness of one or two inches, which accumu lation is sufiicient to plug the boiler fines and prevent adequate generation of steam.

It is the main object of this invention to eliminate the difficulties heretofore encountered in the use of pulverulent fuel with steam engines such as a locomotive by the provision of a new and improved arrangement of water heating elements in the boiler structure whereby a larger combustion chamber is provided and a maximum amount of steam may be obtained from a minimum amount of fuel; and the further provision of a novel boiler or steam generating device having new and improved means for depositing and collecting the ash and unconsumed portions of the fuel to prevent accumulation of honeycomb on the boiler flue sheet.

A still further object of the invention is the provision of a new and improved steam generating plant that is simple in construction, inexpensive to manufacture and install, and that is efficient and economical in'operation.

Other and further objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, in which Fig. 1 is a longitudinal, vertical section of a portion of a steam engine equipped with a pulverized fuel feeding device, embodying the invention;

Fig. 2 is a longitudinal section on the broken line 2-2 of Fig. 1;

Fig. 3 is a vertical section on line 3-3 of '30 Fig. 1;

Fig.4 is a vertical section on line 4-4 of Fig. 1;

Fig. 5 is a perspective view of one of the removable fire resisting blocks or elements; and

Fig. 6 is a view similar to Fig. 2, of the forward portion of the combustion chamber, showing one of the fire resisting blocks or elements partially removed.

Referring now to the drawings, the reference character 10 designates generally a locomotive and 11 a tender therefor. The forward portion of the locomotive is provided with a boiler 12 comprising the barrel 13, the fiues or boiler tubes 14 and the rear tube or flue sheet 15, all of which are of the usual or any approved construction.

The rear portion of the locomotive is provided with a firebox comprising a combustion or ignition chamber 16 and a heating chamber separated by a baflle containing water as will 30 presently appear. The bottom walls of the combustion chamber 16 are in' the form of water containing tables or plates 17 and 18 which are in communication with the hollow mud ring 19 i and slope inwardly and downwardly therefrom. 35 Their inner edges are spaced apart to provide an opening 21 for the escape of ash and the unconsumed portions of the fuel which, upon being deposited upon these plates is caused to move along the plates by the impacts of the fuel delivered by the feeding device and to slide down the same bythe vibration incident to the travel of the locomotive, as will presently appear.

A receptacle 22 is suspended beneath the opening 21 for receiving the fuel ash and unconsumed material. This receptacle has inclined bottom walls 23 and 24, see Fig. l, which slope toward a'discharge passage25 which is adapted to' be closed by a removable closure 26. The receptacle 22 may, if desired, be faced or lined with fire clay or fire brick 27, as indicated in Fig. 1.

The combustion chamber is so constructed as to adapt it especially for use in the burning of pulverized fuel and in the use of such fuel it is desirable to construct all the enclosing walls in such a manner that water from the boiler may circulate through the same, whereby a maximum heating area is provided for increasing the efliciency of the steam generating elements. By

their lower ends in communication with the hollow mud ring 19 and their upper ends secured in the walls of a steam drum which extends from the backhead 32 ofj'the locomotive forwardly to the boiler barrel 13. The tubes 31 extend upwardly from the mud ring slightly spaced from the side sheets or jacket 70 of the firebox, and a layer of fire clay or fire brick 33 is interposed between the tubes and sheets for refleeting the heat onto the tubes for protecting the side sheets and for preventing undue radiation of the heat. This layer of fire brick or clay is continued to the drum 35 so as to provide an impervious concave wall extending from the mud ring upward and then inward to said drum;

A partition or bafile wall 34is provided at the forward end of the firebox. This wall is spaced from the back tube sheet 15 to form what for convenience of description will be termed a heating chamber 36. This wall is hollow and is in communication with a header 37 and also with the tables or plates 1'7 and 18 as clearly shown in Fig. 1 of the drawings. This wall constitutes the forward end of the combustion chamber. The sides of this chamber at the rearthereof are formed by two sets of tubes 38 and 39 which are in communication with the hollow mud ring 19 at their lower ends, and with the drum 35 at their upper ends. The wall 34 tapers toward its upper end and this tapered portion is connected to the drum 35 by the two tubes 30.

These two sets of tubes 38 and 39 converge inwardly from the mud ring and may be curved downwardly to form passageways 40 and 41 between the same and the tubes 31, see Fig. 3. Layers of fireclay or firebrick 42 and 43 are supported by the two sets of tubes 38 and. 39 respectively.

The walls formed by the tubes 38 and 39 and the supported layer of firebricks 42 and 43 stop short'of the rear end of the combustion chamber whereby the heated gases may pass from the rear portion of said chamber into the passages 40 and 41 and through these passages into the heating chamber 36 from whence they pass into the fines 14.

"The baflie or wall 34 stops short of the drum 35 and the space between it and the drum is closed by a pair of blocks or bricks 45 of refractory material, each of which is provided with a groove 46 in its back face extending longitudinally thereof for engaging the rearmost portion of the tubes 30 as indicated in Figs. 2 and 6. The opposite face of the block is formed on a curve as at 4'7 to permit the block to be turned as shown in Fig. 6 so that it may be removed.

When the blocks are in the position shown in Fig. 2 they will close the space between the upper end of the wall 34 and the drum 35 so as to prevent the heated gases of combustion from passing from the ignition or combustion chamber 16 into the heating chamber 36, thereby compelling the heated gases to return to the rear end of the firebox in order to escape into the 'form'the side walls of said chamber. bottom walls of the chamber are formed by the heating chamber 36 through the passages 40 and 41.

The heating chamber 36 is formed by water containing elements such as the tubes 48 and 49 which have their lower ends in communication with the header 3! and their upper ends in communication with the drum 35, each set of tubes being curved outwardly and then inwardly to The top and drum 35 and header 37 respectively.

Layers of refractory material 51 and 52 are inserted between the tubes 48 and 49 and the metallic shell 53. The metallic shell 53 is of less diameter than the shell formed by the side sheets and the space between the two is closed by suitable plates 54 and 55, see Fig. 4.

The steam generating elements of the engine and the arrangement of the same to form the combustion chamber are adapted for the burning of fuel supplied to the combustion chamber in a fluid mass, such for instance as oil, pulverized fuel and the like. It is especially adapted for the use of pulverized fuel.

As heretofore mentioned, one great difficultyin burning pulverized fuel in a locomotive boiler is the accumulation of solid material, commonly referred to as honeycomb on the tube sheet of the boiler, especially if a coal having a relatively low fusing point ash be used. As the combustible portion of a coal particle is consumed, the ash content is swept along with the current of products of combustion until it meets the back tube sheet which is transverse to the direction of the travel of the gas and ash. When the lat' ter impinges against the tube sheet or ends of the tubes it is in a semi-molten or tacky condition and tends to adhere to the metal and build up by accretion until the draft becomes choked.

The present invention seeks to eliminate this difficulty by providing means whereby the solid particles of the consumed fuel will be deposited within the combustion chamber 16 thereby eliminating the accumulation of solid material on the back tube sheet and boiler tubes. 'As shown, a device for utilizing pulverized coal as the fuel is disclosed in the drawings. It is understood, however, that this is by way of example only, and that other devices for feeding the same may be employed.

As illustrated, fuel is fed forwardly from the tender 11 by the conveyor 56 which is operated by a suitable motor 57 in a manner well known in the art. The fuel is reduced by the crushing mechanism 58 to pulverulent form, which is fed forwardly through the conduit 59 by a fan 61. Since the details of the fuel crushing and feeding device constitute no part of the present invention it is not thought necessary to further illustrate or describe the same.

In order to cause the solid particles of the consumed fuel to be deposited in the combustion chamber 16, the nozzles 62 and 63 are directed laterally and downwardly toward the plates or tables 17 and 18 in such a manner that the ash and solid portions of the consumed fuel will strike on intermediate portions of the water cooled plates or tables at an angle, thereby causing said ash and solid particles to flow along the tables or plates by the continual impact of the oncoming ash and other material from the rear. The momentum of these particles will carry the same beyond the space where they will be affected by the heated gases when they return toward the rear of the combustion chamber, that is, beyond the return path of the heated gases, consequently these gases will be substantially free of ash or other particles of matter.

By directing the fuel nozzles 62 and 63 downwardly so that the deposits of the ash and other particles of the consumed fuel will be localized on the forward portions of the plates or tables 17 and 18 instead of being deposited on the top and side walls of the combustion chamber and on the tube sheet and boiler flues, thereby partially insulating the same, the effectiveness of the steam generating elements of the boiler will be materially increased. This is considered an important feature of the invention because of the increased efiiciency of the boiler and the elimination of the molten ash before it reaches the flue sheet.

The fuel feeding nozzles 62 and 63 may extend into the boiler through the firedoor opening 64 or through a specially prepared opening beneath the conventional firedoor opening. The opening 64 is provided with a partition 65 below which the nozzles extend. Plates 66 and 67 are provided for the opening 64. The opening or as shown is formed in a water leg 58 that surrounds said opening and is in communication with the hollow mud ring 19 as clearly shown in Fig. l of the drawings. Tubes 69 connect the upper portion of the water leg with the drum 35.

In the operation of the device, the pulverized fuel is fed by the nozzles into the combustion chamber 16. The nozzles being directed downwardly diagonally the ash and other particles of consumed fuel will strike the inclined tables or plates 17 and 18 at an angle and will be caused to flow forwardly and downwardly somewhat in the form of slag toward the opening 21 into the ash or slag receptacle 22. These tables or plates Will become highly heated, thereby heating the water contained therein.

The heated gases will return along the upper portion of the combustion chamber thereby heating the water in the tubes 38 and 39. The heated gases passing along the passages to and 41 and into the heating chamber 36 will heat the water in the tubes 31 in said passages and in the tubes 48 and 49 forming the walls of said heating chamber. From the heating chamber the gases pass into the fiues 14 of the boiler for heating the water contained therein.

The water on becoming heated in the tables or plates 17 and 18 will flow upwardly to the hollow mud ring and from thence upwardly with the water heated in the tubes 31, 38, 39, 48 and 49. The water in these tubes will be heated by the gases and certain portions converted into steam, which, with the remaining portions, will flow into the drum 35, the same being replaced in the tubes by the cooler water from the boiler through the header 37 which leads from the lower portions of the barrel 13 to the baffle or back wall 34 as shown in Fig. 1. The back wall is in communication with the lower portions of the tables or plates 17 and 18 by the conduits or passages 71, see Fig. 1.

The cooler water in the boiler barrel passes through the header into the wall 34 and some of it passes upwardly into the wall and the steam formed will pass through the tubes 30 into the header along with the heated water. The restricted passages formed by the tube 30 and the tapered upper end of the wall prevents the too rapid circulation of the water upwardly through the wall, whereby a considerable portion of the water passing into said wall will pass on through into the plates 1'? and 18 and hollow mud ring where it becomes heated and rises in the tubes forming the side and front walls of the firebox as previously described.

It will thus be seen that the side walls of the firebox, the walls forming the sides and most of the top of the combustion and heating chambers, are formed of tubes. The exposed surfaces of these tubes being curved in cross-section correspond to the surface of a corrugated sheet, and hence the heating surfaces of these walls are greatly increased and the efiiciency of the steam generating elements multiplied.

I claim as my invention:

In a locomotive, a firebox, a boiler barrel, a drum extending from the baclrwall of said locomotive to said boiler barrel over said firebox, said drum being in communication with said boiler barrel, a hollow mud ring, a plurality of water tubes extending upwardly and then laterally inwardly to said drum to form the sides of said firebox, a layer of refractory material engaging the outer surfaces of said tubes, hollow plates sloping inwardly and downwardly from said mud ring adjacent the sides of the firebox and spaced apart at their inner edges, said plates forming the bottom wall of the firebox, a hollow wall extending transversely across said firebox for dividing the same into a combustion and a heating chamber, a header between the lower portion of said wall and said boiler barrel providing communication therebetween, water tubes connected to said header and said drum, said tubes extending upwardly and curved outwardly to form the sides of said heating chamber, water tubes between the upper portion of said hollow transverse wall and said drum, refractory material closing the space between said last named tubes and forming with said hollow transverse wall the front wall of said combustion chamber, water tubes extending upwardly and inwardly and then upwardly connecting said hollow mud ring and drum, and a layer of refractory material on said last named tubes for forming with said pipes the top wall of said combustion chamber, said combustion chamber having substantially the same cross sectional area throughout, said top wall of the combustion chamber stopping short of the backhead of said firebox to form passageways for heated gases to said heating chamber.

ANDREW M. HUNT. 

